A158284 List of pairs p, p+2 where p is prime and p and p+2 contain the same number of prime digits.

3, 5, 5, 7, 13, 15, 23, 25, 29, 31, 43, 45, 53, 55, 73, 75, 83, 85, 89, 91, 103, 105, 109, 111, 113, 115, 163, 165, 173, 175, 193, 195, 223, 225, 229, 231, 233, 235, 263, 265, 283, 285, 293, 295, 313, 315, 353, 355, 373, 375, 383, 385, 389, 391, 409, 411, 433

Offset

1,1

Comments

Prime digits are 2, 3, 5 or 7.

Links

Table of n, a(n) for n=1..57.

Mathematica

snpdQ[n_]:=Count[IntegerDigits[n], _?PrimeQ]==Count[IntegerDigits[n+2], _?PrimeQ]; {#, #+2}&/@Select[Prime[Range[100]], snpdQ]//Flatten (* Harvey P. Dale, Dec 04 2017 *)

Crossrefs

Cf. A077800.

Sequence in context: A073340 A118409 A162779 * A090941 A090917 A226540

Adjacent sequences: A158281 A158282 A158283 * A158285 A158286 A158287

Keyword

nonn,base,less

Author

Juri-Stepan Gerasimov, Mar 15 2009

Extensions

(13,15) inserted, (23,25) inserted, and all other numbers replaced by R. J. Mathar, May 19 2010

Definition changed to match the terms by N. J. A. Sloane, Dec 03 2017

Status

approved